<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>网格系统</title>
    <link
      href="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/bootstrap/4.6.1/css/bootstrap.min.css"
      type="text/css"
      rel="stylesheet"
    />
  </head>
  <body>
    <!-- 
        网格系统:
        把网页横向分成12分,可以任意组合,简化整个网页的布局,不需要自己再写各种浮动或者清除浮动了

        可视化网址: https://www.runoob.com/try/bootstrap/layoutit/
     -->
    <!-- 版心1140px版心 -->
    <div class="container">
      <!-- 贯穿版心 -->
      <!-- <div class="container-fruid"> -->
      <!-- 行 -->
      <div class="row">
        <!-- 列 -->
        <div class="col-12">标题</div>
      </div>
      <div class="row">
        <div class="col-3">AAA</div>
        <!-- 列偏移 -->
        <div class="col-3 offset-6">BBB</div>
      </div>
      <div class="row">
        <div class="col-4">侧边栏</div>
        <div class="col-8">
          <div class="row">
            <!-- 
              媒体查询
              col-xl-       ≥ 1200px
              col-lg-       ≥ 992px
              col-md-       ≥ 768px
              col-sm-       ≥ 576px
              col-          < 576px
             -->
            <div class="col-md-3 col-sm-4 col-6">111</div>
            <div class="col-md-3 col-sm-4 col-6">222</div>
            <div class="col-md-3 col-sm-4 col-6">333</div>
            <div class="col-md-3 col-sm-4 col-6">444</div>
          </div>
        </div>
      </div>
      <div class="row">
        <div class="col-12">版权</div>
      </div>
    </div>

    <script
      src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/jquery/3.6.0/jquery.min.js"
      type="application/javascript"
    ></script>
    <script
      src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/bootstrap/4.6.1/js/bootstrap.min.js"
      type="application/javascript"
    ></script>
  </body>
</html>
